void DrawArrow( float px, float py, float pz,
float nx, float ny, float nz,
double arrowEndWidth, double arrowEndLength )
{
GLdouble normal[3], cross[3], zaxis[3];
GLdouble angle;
#define DegreesToRadians (3.14159265 / (GLfloat) 180.0)
normal[0] = nx; normal[1] = ny; normal[2] = nz;
double len = sqrt(nx*nx + ny*ny + nz*nz);
if (len < 1E-6)
return;
glPushMatrix();
glTranslatef( px, py, pz );
glBegin( GL_LINES );
glVertex3f( 0.0, 0.0, 0.0 );
glVertex3f( nx, ny, nz );
glEnd();
// normalize the normal vector
normal[0] /= len;
normal[1] /= len;
normal[2] /= len;
// determine angle between z axis and normal
zaxis[0] = 0; zaxis[1] = 0; zaxis[2] = 1;
angle = acos( zaxis[0]*normal[0] + zaxis[1]*normal[1] + zaxis[2]*normal[2] )/DegreesToRadians;
if ( angle != 0.0 )
{
// find the axis of rotation
CROSSPRODUCT( zaxis[0], zaxis[1], zaxis[2],
normal[0], normal[1], normal[2],
cross[0], cross[1], cross[2] );
glRotatef( angle, cross[0], cross[1], cross[2] );
}
// move to end of normal vector
glTranslatef( 0.0, 0.0, len );
/*
glScalef(0.3,0.3,0.3);
#ifdef EIFFEL140VOX
glScalef(2.0,2.0,2.0);
#endif
#ifdef SPOON100VOX
glScalef(2.0,2.0,2.0);
#endif
*/
glutSolidCone( len*arrowEndWidth, len*arrowEndLength, 12, 1 );
glPopMatrix();
}
/*>REAL blPointLineDistance(REAL Px, REAL Py, REAL Pz,
REAL P1x, REAL P1y, REAL P1z,
REAL P2x, REAL P2y, REAL P2z,
REAL *Rx, REAL *Ry, REAL *Rz,
REAL *frac)
------------------------------------------------------
*//**
\param[in] Px Point x coordinate
\param[in] Py Point y coordinate
\param[in] Pz Point z coordinate
\param[in] P1x Line start x coordinate
\param[in] P1y Line start y coordinate
\param[in] P1z Line start z coordinate
\param[in] P2x Line end x coordinate
\param[in] P2y Line end y coordinate
\param[in] P2z Line end z coordinate
\param[out] *Rx Nearest point on line x coordinate
\param[out] *Ry Nearest point on line y coordinate
\param[out] *Rz Nearest point on line z coordinate
\param[out] *frac Fraction along P1-P2 of R
\return Distance from P to R
Calculates the shortest distance from a point P to a line between
points P1 and P2. This value is returned.
If the Rx,Ry,Rz pointers are all non-NULL, then the point on the
line nearest to P is output.
If the frac pointer is non-NULL then the fraction of R along the
P1-P2 vector is output. Thus:
R==P1 ==> frac=0
R==P2 ==> frac=1
Thus if (0<=frac<=1) then the point R is within the line segment
P1-P2
- 16.11.99 Original By: ACRM
- 07.07.14 Use bl prefix for functions By: CTP
*/
REAL blPointLineDistance(REAL Px, REAL Py, REAL Pz,
REAL P1x, REAL P1y, REAL P1z,
REAL P2x, REAL P2y, REAL P2z,
REAL *Rx, REAL *Ry, REAL *Rz,
REAL *frac)
{
VEC3F A, u, Q, PQ, PR, QP, QP2;
REAL alen, len, f;
/* Calculate vector from P1 to P2 */
A.x = P2x - P1x;
A.y = P2y - P1y;
A.z = P2z - P1z;
/* Calculate length of this vector */
alen = sqrt(DOTPRODUCT(A,A));
/* If the two ends of the line are coincident then return the distance
from either of them
*/
if(alen==(REAL)0.0)
{
len = sqrt((Px-P1x)*(Px-P1x) +
(Py-P1y)*(Py-P1y) +
(Pz-P1z)*(Pz-P1z));
if(frac!=NULL)
*frac = 0.0;
if(Rx != NULL && Ry != NULL && Rz != NULL)
{
*Rx = P1x;
*Ry = P1y;
*Rz = P1z;
}
return(len);
}
/* Calculate the unit vector along A */
u.x = A.x / alen;
u.y = A.y / alen;
u.z = A.z / alen;
/* Select Q as any point on A, we'll make it P1 */
Q.x = P1x;
Q.y = P1y;
Q.z = P1z;
/* Calculate vector PQ */
PQ.x = Q.x - Px;
PQ.y = Q.y - Py;
PQ.z = Q.z - Pz;
/* Vector PR is the cross product of PQ and the unit vector
along A (i.e. u)
*/
CROSSPRODUCT(PQ, u, PR);
/* And the length of that vector is the length we want */
len = sqrt(DOTPRODUCT(PR,PR));
if(frac != NULL || Rx != NULL || Ry != NULL || Rz != NULL)
{
/*** OK we now know how far the point is from the line, so we ***
*** now want to calculate where the closest point (R) on the ***
*** line is to point P ***/
/* Find the projection of QP onto QP2 */
QP.x = Px - Q.x;
QP.y = Py - Q.y;
QP.z = Pz - Q.z;
QP2.x = P2x - Q.x;
QP2.y = P2y - Q.y;
QP2.z = P2z - Q.z;
f = DOTPRODUCT(QP, QP2) / sqrt(DOTPRODUCT(QP2, QP2));
if(frac != NULL)
{
*frac = f/alen;
}
/* Find point R: this is the fraction f of the unit vector along
P1-P2 added onto Q
*/
if(Rx != NULL && Ry != NULL && Rz != NULL)
{
*Rx = Q.x + f * u.x;
*Ry = Q.y + f * u.y;
*Rz = Q.z + f * u.z;
}
}
return(len);
}
